Molded polymeric cradle for containing an anode in an electrolytic capacitor from high shock and vibration conditions

ABSTRACT

A polymeric cradle molded about the periphery of an anode pellet in an electrolytic capacitor is described. The polymeric cradle contacts between a welding strap surrounding the butt seam between mating “clam shell” casing portions and the anode pellet sidewall. This prevents the anode pellet from moving along both an x- and y-axes. Having the cathode active material contacting the opposed major casing sidewalls being in a closely spaced relationship with the anode pellet through an intermediate separator prevents movement along the z-axis. The resulting capacitor is particularly well suited for use in high shock and vibration conditions.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority based upon provisionalapplication Ser. No. 60/548,954, filed Mar. 1, 2004.

BACKGROUND OF THE INVENTION

The present invention generally relates to a capacitor and, moreparticularly, to a capacitor capable of being subjected to high shockand vibration forces without failing.

SUMMARY OF THE INVENTION

Capacitors are used frequently in applications where high shock andvibration levels are experienced. A notable example is in the oil andgas industry where “measurement while drilling” applications can causesevere stress forces to a capacitor. Under high shock and vibrationconditions, capacitors without adequate stabilization are capable offailing due to movement of the electrodes within the case, for examplethe anode pellet in an electrolytic capacitor. This movement can resultin mechanical failure of the anode pellet lead rendering the capacitorinoperative. In that respect, mechanical stabilization of the anodepellet inside the casing is important to improving the reliability andsafety of capacitors subjected to high shock and vibration conditions.

The capacitor of the present invention provides such mechanicalstabilization through a surrounding polymeric cradle that contactsbetween the casing sidewall and the anode pellet sidewall to lock theanode in place. Alternatively, the polymeric cradle contacts between awelding strap surrounding the butt seam between mating “clam shell”casing portions and the anode pellet sidewall. This structure preventsthe anode pellet from moving along both an x- and y-axes. Having thecathode active material contacting the opposed major casing sidewallsbeing in a closely spaced relationship with the anode pellet through anintermediate separator prevents movement along the z-axis.

These and other aspects of the present invention will become moreapparent to those skilled in the art by reference to the followingdescription and to the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a capacitor 10 according to the presentinvention.

FIG. 2 is a side elevational view of an anode 12 having an embeddedanode wire 34 extending from a notch 32 thereof.

FIG. 3 is a cross-sectional view of a glass-to-metal seal 38 for ananode lead 36.

FIG. 4 is a side elevational view of the anode lead 36 including theglass-to-metal seal 38 connected to the embedded wire 34 of anode 12.

FIG. 5 is a plan view of the anode 12 including the glass-to-metal seal38 positioned in a mold portion 48 with a plurality of spacers 54A to54J positioned about its periphery and interior of a welding strap 50.

FIG. 6 is a plan view showing polymeric material being injected into themold shown in FIG. 5.

FIG. 7 is a side elevational view showing the anode 12 being held inposition inside the weld strap 50 by the polymeric web 58 and integralprotrusions 58A to 58J after being removed from the mold shown in FIG.6.

FIG. 8 is a side elevational view of a casing portion 20 supporting acathode active material 14 on a face wall 28 thereof.

FIG. 9 is a side elevational view showing the assembly of FIG. 7comprising the anode 12, polymeric material 58 and welding strap 50after being nested in the casing portion 20 of FIG. 8.

FIG. 10 is a cross-sectional view along line 10-10 of FIG. 9.

FIGS. 10A and 10B are alternate embodiments similar to the view shown inFIG. 10, but with the capacitor housed in different casings.

FIG. 11 is a plan view of the anode 12 including the glass-to-metal seal38 positioned in a mold portion 48 with a plurality of spacer pegs 102Ato 102L positioned about its periphery and interior of the welding strap50.

FIG. 12 is a plan view showing polymeric material being injected intothe mold shown in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, FIG. 1 is a perspective view showing acapacitor 10 according to the present invention. The capacitor 10comprises an anode 12 (FIG. 2) of an anode active material and a cathodeof a cathode active material 14 (FIG. 8) housed inside a hermeticallysealed casing 16. The capacitor electrodes are operatively associatedwith each other by a working electrolyte (not shown) contained insidethe casing, as will be described in detail hereinafter. The capacitor 10is of an electrolyte type with the cathode comprising a conductivesubstrate having capacitive properties.

As particularly shown in FIGS. 1 and 8 to 10, the casing 16 is of ametal material comprising first and second casing portions 18 and 20.Casing portion 18 comprises a surrounding sidewall 22 extending to aface wall 24. Similarly, casing portion 20 comprises a surroundingsidewall 26 extending to a face wall 28. Sidewall 26 is sized so thatsidewall 22 is in an overlapping relationship therewith. Then, thecasing portions 18, 20 are hermetically sealed together by welding theoverlapping sidewalls 22, 26 where they contact. The weld 30 is providedby any conventional means; however, a preferred method is by laserwelding.

The mating casing portions 18, 20 are preferably selected from the groupconsisting of tantalum, titanium, nickel, molybdenum, niobium, cobalt,stainless steel, tungsten, platinum, palladium, gold, silver, copper,chromium, vanadium, aluminum, zirconium, hafnium, zinc, iron, andmixtures and alloys thereof. Preferably, the face and sidewalls of thecasing portions have a thickness of about 0.005 to about 0.015 inches.

The active material of the anode 12 is typically of a metal selectedfrom the group consisting of tantalum, aluminum, titanium, niobium,zirconium, hafnium, tungsten, molybdenum, vanadium, silicon, germanium,and mixtures thereof in the form of a pellet. As is well known by thoseskilled in the art, the anode metal in powdered form, for exampletantalum powder, is compressed into a pellet having a notch 32 fromwhich an embedded anode wire 34 (FIGS. 2, 4 to 7 and 9) extends. Theanode wire 34 preferably comprises the same material as the anode activematerial. The anode pellet is sintered under a vacuum at hightemperatures and then anodized in a suitable electrolyte. The anodizingelectrolyte fills the pores of the pressed powder body and a continuousdielectric oxide is formed thereon. In that manner, the anode 12 andextending wire 34 are provided with a dielectric oxide layer formed to adesired working voltage. The anode can also be of an etched aluminum,niobium, or titanium foil.

After the anode 12 and extending wire 34 are anodized to the desiredformation voltage, the dielectric oxide is removed from the wireconnected to an anode lead 36 supported in an insulative glass-to-metalseal 38 (GTMS). The weld and lead are then re-anodized. Theglass-to-metal seal 38 comprises a ferrule 40 defining an internalcylindrical through bore or passage 42 of constant inside diameter. Aninsulative glass 44 provides a hermetic seal between the bore 42 and theanode lead 36 passing there through. The anode lead 36 has a J-shapedproximal portion 36A that is subsequently connected to a crook in theanode wire 34 such as by laser welding to secure them together. Theglass 44 is, for example, ELAN® type 88 or MANSOL™ type 88. As shown inFIGS. 1 and 9, in the final capacitor assembly the GTMS 38 electricallyinsulates the anode lead 36 connected to the anode wire 34 from themetal casing 18.

A separator 46 of electrically insulative material in the shape of a bagcompletely surrounds and envelops the anode 12 except the extending wire34. The separator 46 prevents an internal electrical short circuitbetween the anode 12 and cathode active materials 14 in the assembledcapacitor and has a degree of porosity sufficient to allow flow therethrough of the working electrolyte during the electrochemical reactionof the capacitor 10. Illustrative separator materials include woven andnon-woven fabrics of polyolefinic fibers including polypropylene andpolyethylene or fluoropolymeric fibers including polyvinylidenefluoride, polyethylenetetrafluoroethylene, andpolyethylenechlorotrifluoroethylene laminated or superposed with apolyolefinic or fluoropolymeric microporous film, non-woven glass, glassfiber materials and ceramic materials. Suitable microporous filmsinclude a polyethylene membrane commercially available under thedesignation SOLUPOR® (DMS Solutech), a polytetrafluoroethylene membranecommercially available under the designation ZITEX® (Chemplast Inc.), apolypropylene membrane commercially available under the designationCELGARD® (Celanese Plastic Company, Inc.), and a membrane commerciallyavailable under the designation DEXIGLAS® (C. H. Dexter, Div., DexterCorp.). Cellulose based separators also typically used in capacitors arecontemplated by the scope of the present invention. Depending on theelectrolyte used, the separator can be treated to improve itswettability, as is well known by those skilled in the art.

As shown in FIG. 5, the anode 12 connected to the anode lead 36supported in the GTMS 38 is then positioned inside a mold portion 48. Ametal welding strap 50 is also positioned in the mold portion 48 in agenerally enclosing, but spaced relationship with the anode 12 and GTMS38. The welding strap 50 is discontinuous at 52 to provide a space forthe GTMS 38. As will be described in detail hereinafter, the metal strap50 serves as a backing to protect the anode 12 and separator 46 from thelaser welding light when the casing portions 18 and 20 are welded toeach other during final capacitor assembly.

Once the anode 12 and GTMS 38 enclosed by the welding strap 50 areproperly positioned in the mold portion 48, a plurality of spacers 54Ato 54J are positioned about the periphery of the anode. The spacers areshaped to conform to the peripheral contour of the anode sidewallportion that they contact. However, the spacers 54A to 54J are spacedfrom each other as well as from the welding strap 50.

After the mold is closed, a nozzle 56 is hooked up to the mold. Thenozzle 56 is used to inject a polymer material into the void between thewelding strap 50 and the spacers 54A to 54J and the uncovered peripheralportions of the anode side wall. If desired, there can be more than onenozzle positioned at spaced locations about the periphery of the mold.The polymeric material is preferably of a fast curing type including apolyolefin, a fluoropolymer, a hot melt adhesive, or a UV curableadhesive. A relatively slow curing silastic material is also useful.This forms a polymeric cradle around the sidewall perimeter of the anode12. Specifically, the cradle comprises a surrounding web 58 of thepolymeric material supporting integral protrusions 58A to 58I formedbetween the spacers 54A to 54J. The surrounding web 58 contacts thewelding strap 50 while the protrusions 58A to 58I contact the separator46 along the anode sidewall. A rather large protrusion 58J is formedbetween spacers 54A and 54J to completely encase the GTMS 38 includingthe insulated anode lead 36 connected to the anode wire 34. The anode 12held in position inside the weld strap 50 by the polymeric cradlecomprising the web 58 and integral protrusions 58A to 58J is thenremoved from the mold 48 as an assembly (FIG. 7).

The cathode active material 14 preferably coats the face walls 24, 28,spaced from the respective sidewalls 22, 26. The pad printing processdescribed in U.S. patent application Ser. No. 10/920,942, filed Aug. 18,2004, is preferred for making such a coating. Ultrasonically generatedaerosol as described in U.S. Pat. Nos. 5,894,403; 5,920,455; 6,224,985;and 6,468,605, all to Shah et al., are also suitable deposition methods.These patents and patent application are assigned to the assignee of thepresent invention and incorporated herein by reference.

As shown in FIG. 8, casing portion 20 is provided with the cathodeactive material 14 coated on its face wall 28 in a pattern thatgenerally mirrors the shape of the anode 12. The cathode active material14 has a thickness of about a few hundred Angstroms to about 0.1millimeters and is either directly coated on the inner surface of theface wall 28 or it is coated on a conductive substrate (not shown) inelectrical contact with the inner surface of the face wall. The othercasing portion 18 has the cathode active material 14 similarly coated onits face wall 24 or on a conductive substrate secured to the innersurface of the face wall in electrical contact therewith. In thatrespect, the face walls 24, 28 may be of an anodized-etched conductivematerial, have a sintered active material with or without oxidecontacted thereto, be contacted with a double layer capacitive material,for example a finely divided carbonaceous material such as graphite orcarbon or platinum black, a redox, pseudocapacitive or an underpotential material, or be an electroactive conducting polymer such aspolyaniline, polypyrole, polythiophene, polyacetylene, and mixturesthereof.

According to one preferred aspect of the present invention, the redox orcathode active material 14 includes an oxide of a first metal, thenitride of the first metal, the carbon nitride of the first metal,and/or the carbide of the first metal, the oxide, nitride, carbonnitride and carbide having pseudocapacitive properties. The first metalis preferably selected from the group consisting of ruthenium, cobalt,manganese, molybdenum, tungsten, tantalum, iron, niobium, iridium,titanium, zirconium, hafnium, rhodium, vanadium, osmium, palladium,platinum, nickel, and lead.

The cathode active material 14 may also include a second or more metals.The second metal is in the form of an oxide, a nitride, a carbon nitrideor carbide, and is not essential to the intended use of the conductiveface walls 24, 28 as a capacitor electrode. The second metal isdifferent than the first metal and is selected from one or more of thegroup consisting of tantalum, titanium, nickel, iridium, platinum,palladium, gold, silver, cobalt, molybdenum, ruthenium, manganese,tungsten, iron, zirconium, hafnium, rhodium, vanadium, osmium, andniobium. In a preferred embodiment of the invention, the cathode activematerial 14 includes an oxide of ruthenium or oxides of ruthenium andtantalum.

As shown in FIG. 9, the anode 12 surrounded by the polymeric cradle andthe welding strap 50 as an assembly is then nested in the casing portion20 with the GTMS 38 received in an opening 60 (FIG. 8) in the casingsidewall 26. The ferrule 40 of the GTMS has a distal step 40A (FIG. 3)that fits into the casing opening 60 in a tight fitting relationship.The welding strap 50 is likewise sized to fit inside the perimeter ofthe casing sidewall 26 in a closely spaced relationship. The ferrule 40is then secured to the casing sidewall 26 such as by laser welding. Thisprovides the anode 12 secured inside the casing portion 20 held inposition by the polymeric cradle comprising the web 58 and integralprotrusions 58A to 58J and the welding strap 50. In this position, theanode major face wall 12 (FIG. 10) is resting on the casing sidewall 26.However, the intermediate separator 46 prevents direct contact betweenthe anode 12 and the cathode active material 14.

The other casing portion 18 is then mated to the casing portion 20 withtheir respective sidewalls 22 and 26 overlapping each other. Thecontinuous weldment 30 provided about the perimeter of the casingsidewalls 22 and 26, such as by laser welding, secures the casingportions 18 and 20 to each other. The welding strap 50, however,prevents the laser light from penetrating into the interior of thecapacitor to damage the anode 12 and separator 46 among other heatsensitive components.

A working electrolyte (not shown) is then provided in the capacitorthrough an opening in one of the casing portions 18, 20. A suitableworking electrolyte for the capacitor 10 is described in U.S. Pat. No.6,219,222 to Shah et al., which includes a mixed solvent of water andethylene glycol having an ammonium salt dissolved therein. U.S. Pub.Nos. 2003/0090857 and 2003/0142464 describe other working electrolytesfor the present capacitors. The working electrolyte of the formerpublication comprises water, a water-soluble inorganic and/or organicacid and/or salt, and a water-soluble nitro-aromatic compound while thelatter relates to an electrolyte having de-ionized water, an organicsolvent, isobutyric acid and a concentrated ammonium salt. Thesepublications and patent are assigned to the assignee of the presentinvention and incorporated herein by reference. The electrolyte fillopening is then closed by a hermetic closure (not shown), as is wellknown by those skilled in the art.

The spaces formed between the protrusions 58A to 58J of the polymericcradle provide for the electrolyte to thoroughly wet the anode 12including the enveloping separator 46 and the cathode active materials14 to provide the capacitor 10 in a functional state. The welding strap50 encloses and contacts the polymeric web 58 including protrusions 58Ato 58J that, in turn, contact the separator 46 at the anode sidewall andencase the GTMS 38. This prevents any movement of these componentsshould the capacitor be subject to high shock and vibration conditions.

FIG. 10A shows an alternate embodiment of a casing for the presentcapacitor. The casing comprises portion 20A having a surroundingsidewall 26A extending to a face wall 28A supporting the cathode activematerial 14. The sidewall 26A has a step at its upper end that receiveda plate 24A serving as a second face wall for supporting the cathodeactive material 14. The plate 24A is nested therein. A weld 30 securesthe plate 24A to the sidewall 26A at the step with the upper surface ofthe plate being coplanar with the upper end of the sidewall 26A. Theremaining structure for this capacitor is as previously described.

FIG. 10B shows another embodiment of a casing for the present capacitor.The casing comprises portion 20B having a surrounding sidewall 26Bextending to a face wall 28B supporting the cathode active material 14.A plate 24A rests on the upper edge of the sidewall 26A and serves as asecond face wall for supporting the cathode active material 14. Plate24A extends a short distance out beyond the sidewall 26A. A weld 30 thensecures the plate 24A to the sidewall 26B where the plate overhangs orextends past the sidewall. Also, in this embodiment, the weld strap hasbeen eliminated from the mold shown in FIG. 5 and the height of thepolymeric web is shortened from that shown in the other embodiments.Elimination of the welding strap is possible with the laser beam beingaimed at the corner where the plate 24A extends past the sidewall 26B.The remaining structure for this capacitor is a previously described.

FIGS. 11 and 12 show an alternate embodiment for providing a polymericcradle according to the present invention. The anode 12 connected to theanode lead 36 supported in the GTMS 38 is first positioned inside a moldportion 100. The metal welding strap 50 is also positioned in the moldportion 100 in a generally enclosing, but spaced relationship with theanode 12 and GTMS 38. Once the anode 12 and GTMS 38 enclosed by thewelding strap 50 are properly positioned in the mold portion 100, aplurality of spacer pegs 102A to 102M are positioned about the peripheryof the anode. The pegs 102A to 102L are cylindrically shaped with adiameter to contact both the welding strap 50 and the perimeter of theanode sidewall. A relatively large cylindrically shaped peg 102M ispositioned in a corner of the welding strap 50, but it is not in contactwith the anode sidewall. This peg is for the purpose of maintaining theposition of the welding strap. The pegs 102A to 102L are spaced fromeach other.

After the mold is closed, the nozzle 56 is hooked up to it. As before,the nozzle 56 is used to inject a polymer material into the spaces orgaps between the pegs 102A to 102L and the uncontacted peripheralportions of the anode sidewall. The polymeric material is similar tothat used in the previous embodiment and forms a polymeric cradle 104around the sidewall perimeter of the anode 12. In this case, the cradle104 comprises the surrounding polymeric material contacting between thewelding strap 50 and the anode sidewall. The anode 12 held in positioninside the weld strap 50 by the polymeric cradle 104 is then removedfrom the mold 48 as an assembly for further processing into a functionalcapacitor as previously described with respect to the first embodimentof the present invention continuing with FIG. 9.

The casing 16, including the portions 18, 20, being of a conductivemetal serves as the negative terminal for making electrical connectionbetween the capacitor 10 and its load. A pin (not shown) is welded toone of the casing portions 18, 20 to provide this. The anode lead 36extending outside the capacitor 10 is hermetically sealed from theinterior of the capacitor and insulated from the mating casing portions20, 22 by the GTMS 38 to serve as the positive terminal for thecapacitor 10.

While all of the embodiments described herein show the polymeric cradleused with a single anode pellet, that should not be construed aslimiting. It is contemplate by the scope of the present invention thatthe polymeric cradle can be used with two or more side-by-side anodesprovided in one of the previously described casings. Such a multipleanode design is shown in U.S. Pat. No. 6,850,405 to Mileham et al. Thispatent is assigned to the assignee of the present invention andincorporated herein by reference.

It is appreciated that various modifications to the inventive conceptsdescribed herein may be apparent to those of ordinary skill in the artwithout departing from the spirit and scope of the present invention asdefined by the appended claims.

1. A capacitor, which comprises: a) a first casing portion comprising afirst face wall supporting a first surrounding sidewall and a secondcasing portion comprising a second face wall, wherein the first casingportion is securable to the second casing portion to provide anenclosure for the capacitor; b) a cathode active material supported by,and in electrical contact with, the first and second face walls; c) ananode comprising an anode sidewall extending to first and second majorface walls positioned adjacent to the cathode active material on thefirst and second face walls; d) a separator positioned intermediate theanode and the cathode active material on the first and second facewalls; e) a glass-to-metal seal supported in at least one of the firstand second casing portions to electrically insulate the anode lead fromthe enclosure serving as the cathode terminal; f) a cradle disposedbetween the anode sidewall and the first and second casing portions toprevent the anode from moving inside the enclosure when the capacitor issubjected to shock and vibration forces; and g) a working electrolyteprovided in the enclosure in contact with the anode and cathode activematerial.
 2. The capacitor of claim 1 wherein a welding strap isprovided between the anode and at least the first surrounding sidewallof the first casing portion being mated to the second casing portion. 3.The capacitor of claim 1 wherein the cradle has a web portion with aplurality of protrusions extending from the web and contacting the anodesidewall.
 4. The capacitor of claim 1 wherein the cradle contacts theanode sidewall and a welding strap provided between where the firstcasing portion is secured to the second casing portion.
 5. The capacitorof claim 1 wherein the cradle is of a polymeric material molded aboutthe anode sidewall and at least partially encasing the glass-to-metalseal.
 6. The capacitor of claim 1 wherein the second casing portion is aplate supported at an upper edge of the first surrounding sidewall ofthe first casing portion.
 7. The capacitor of claim 1 wherein the anodeis selected from the group consisting of tantalum, aluminum, titanium,niobium, zirconium, hafnium, tungsten, molybdenum, vanadium, silicon,germanium, and mixtures thereof and the cathode active material isselected from the group consisting of ruthenium, cobalt, manganese,molybdenum, tungsten, tantalum, iron, niobium, iridium, titanium,zirconium, hafnium, rhodium, vanadium, osmium, palladium, platinum,nickel, lead, gold, silver, cobalt, and mixtures thereof.
 8. Acapacitor, which comprises: a) a first casing portion comprising a firstface wall supporting a first surrounding sidewall and a second casingportion comprising a second face wall supporting a second surroundingsidewall, wherein at least a portion of the first casing sidewall issized to fit inside the second casing sidewall to mate the first casingportion with the second casing portion as an enclosure for thecapacitor; b) a cathode active material supported by, and in electricalcontact with, the first and second face walls of the enclosure; c) ananode comprising an anode sidewall extending to first and second majorface walls positioned adjacent to the cathode active material on thefirst and second face walls; d) a separator positioned intermediate theanode and the cathode active material on the first and second facewalls; e) a glass-to-metal seal supported in at least one of the firstand second casing portions to electrically insulate the anode lead fromthe enclosure serving as the cathode terminal; f) a cradle disposedbetween the anode sidewall and the first and second casing sidewalls toprevent the anode from moving inside the enclosure when the capacitor issubjected to shock and vibration forces; and g) a working electrolyteprovided in the enclosure in contact with the anode and cathode activematerial.
 9. The capacitor of claim 8 wherein a welding strap isprovided between the anode and at least the first surrounding sidewallof the first casing portion mated to the second surrounding sidewall ofthe second casing portion.
 10. The capacitor of claim 8 wherein thecradle has a web portion with a plurality of protrusions extending fromthe web and contacting the anode sidewall.
 11. The capacitor of claim 8wherein the cradle contacts the anode sidewall and a welding strapprovided between a seam created by the first surrounding sidewall of thefirst casing portion mated to the second surrounding sidewall of thesecond casing portion.
 12. The capacitor of claim 8 wherein the cradleis of a polymeric material molded about the anode sidewall and at leastpartially encasing the glass-to-metal seal.
 13. A method for providing acapacitor, comprising the steps of: a) providing a first casing portioncomprising a first face wall supporting a first surrounding sidewall,wherein a cathode active material is in electrical contact with thefirst casing face wall; b) providing an anode comprising an anodesidewall extending to first and second major face walls, wherein ananode wire extends from the anode; c) supporting an anode lead in aglass-to-metal seal and connecting the anode lead to the anode wire; d)enveloping the anode in a separator; e) providing a cradle in asurrounding and contacting relationship with the anode sidewall; f)nesting the anode including the surrounding cradle in the first casingportion with the first major face wall of the anode adjacent to thecathode active material and wherein the glass-to-metal seal is at leastpartially supported by the first casing sidewall with the anode leadextending there from; g) providing a second casing portion comprising asecond face wall having the cathode active material in electricalcontact there with and adjacent to the second major face wall of theanode; h) welding the first casing portion to the second casing portionto provide an enclosure for the capacitor; and i) providing anelectrolyte in the enclosure in contact with the anode and cathodeactive material.
 14. The method of claim 13 including positioning theanode enveloped by the separator in a mold interior of a welding strapand then positioning a plurality of spacers about the anode contactingthe separator at the anode sidewall, but spaced from the welding strap.15. The method of claim 14 including injecting a polymeric material intothe mold to provide the cradle contacting the separator in a surroundingrelationship to the anode sidewall.
 16. The method of claim 15,including encasing a major portion of the glass-to-metal seal in thepolymeric material.
 17. The method of claim 13 including nesting theanode surrounded by the cradle contacting an inner surface of thewelding strap with the welding strap contacting at least one of thefirst and second casing portions.
 18. The method of claim 13 includingpositioning the anode enveloped by the separator in a mold interior of awelding strap and then positioning a plurality of spacers about theanode contacting the welding strap and the separator at the anodesidewall.
 19. The method of claim 13 including positioning the anodeenveloped by the separator in a mold and then positioning a plurality ofspacers about the anode contacting the separator at the anode sidewall.20. The capacitor of claim 13 including selecting the anode from thegroup consisting of tantalum, aluminum, titanium, niobium, zirconium,hafnium, tungsten, molybdenum, vanadium, silicon, germanium, andmixtures thereof and selecting the cathode active material from thegroup consisting of ruthenium, cobalt, manganese, molybdenum, tungsten,tantalum, iron, niobium, iridium, titanium, zirconium, hafnium, rhodium,vanadium, osmium, palladium, platinum, nickel, lead, gold, silver,cobalt, and mixtures thereof.